Science A


Biology B1.7

Chromosomes, found in the cell nucleus, contain many genes. A gene is a section of DNA, which carries coding for a particular protein. Different genes control the development of different characteristics of an organism. Many genes are needed to carry all the genetic information for a whole organism.

The number of genes and chromosomes varies from species to species. For example, cells in human beings have 46 chromosomes that carry about 30,000 genes in each cell; and cells in fruit flies have 8 chromosomes that carry about 13,600 genes.

Inherited Factors

  • Hair Colour
  • Eye colour 
  • Height
  • Skin Colour
  • Lobeless/Lobed ears
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B1.7 cont.

Environmental Factors

Variation can also be due to environent and some is a bit of both inherited and environmental

  • Climate
  • Diet 
  • Religion
  • Language
  • Culture 
  • Lifestyle
  • Accidents
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